Supplements for Energy and Fatigue: What to Test First, What Helps, and Why Adrenal Fatigue Isn't a Diagnosis

This guide is for adults who feel tired most of the time and wonder whether a supplement would help. The honest answer is that a supplement helps mainly when a test shows you are short of something, so testing comes first.

Get checked before you buy anything for energy. In family practice, the most common causes of lasting tiredness are poor or short sleep, sleep apnoea (breathing pauses at night), depression and stress. Anaemia and other physical diseases are less common, and an undiagnosed cancer turned up in 0.6% of tired patients (Maisel 2021). See a doctor promptly if tiredness comes with weight loss you can't explain, fever or night sweats, breathlessness or chest pain, bleeding, or low mood, and reach out the same day if suicidal thoughts come (in the US, call or text 988). If you take a prescribed medicine, don't stop, skip or swap it to feel more awake; some medicines cause tiredness, and your prescriber can review them.

The short version

• Test first: a doctor will usually ask about sleep, mood and medicines, then check a blood count, blood sugar, thyroid (TSH), liver tests and inflammation, plus ferritin (iron stores) in women who still have periods (Maisel 2021).
• Iron, if a blood test finds low iron stores: tiredness eased a little in 4 pooled trials (2 of iron tablets, 2 of iron by drip) of adults, mostly women, with low iron but no anaemia. B Grade B (Houston 2018).
• Vitamin D, if you are low: a single dose eased tiredness in 120 young adults with low levels, against placebo. C Grade C (Nowak 2016).
• B12 with normal levels: in one trial of people with bowel disease, B12 tablets did no better than placebo for tiredness. C Grade C (Scholten 2018).
• Beta-glucans (B), ginseng and CoQ10 (C), rhodiola (D): small or mixed effects in trials with real flaws, and one rhodiola trial found more tiredness than placebo (sections below).
• "Adrenal fatigue" is not a recognised diagnosis, and "adrenal support" pills have contained hidden hormones (Akturk 2018).

What should you test before taking supplements for energy?

Start with the common, fixable causes. A review built on the German family-medicine guideline found sleep problems, sleep apnoea, depression (18.5% of tired patients) and heavy stress at the top of the list. Anaemia and other physical diseases made up 4.3%, and undiagnosed cancer 0.6%. Its basic work-up is a history and examination, then simple blood tests: blood count, blood sugar, CRP or ESR (inflammation), liver tests and TSH, with ferritin added for women who still have periods (Maisel 2021; Stadje 2016).

The same review lists medicines that can make you tired, including antihistamines, benzodiazepine sedatives, blood pressure medicines, opioids and antipsychotics, along with alcohol. Snoring or nodding off at the wheel points to sleep apnoea, which needs a sleep assessment, not a supplement.

Does iron give you energy?

B Grade B, but only when a blood test shows low iron stores. Pooling 4 trials (714 people, mostly women; 2 gave iron tablets and 2 gave iron by drip) of adults with low iron but normal haemoglobin, iron eased self-reported tiredness a little in both kinds, with no change in fitness tests (Houston 2018). In 198 tired women who still had periods, with ferritin under 50 and no anaemia, fatigue scores fell by 47.7% on iron against 28.8% on placebo over 12 weeks; mood and quality of life did not change (Vaucher 2012). On our fatigue evidence page, iron's only graded row is anxiety (C, no effect); for tiredness itself, the 4 pooled trials point the same way, so it is grade B here, as in our iron guide.

Start iron only once a blood test confirms low iron or ferritin. Don't take it if you have haemochromatosis (an inherited iron overload, found in about 4 in 1,000 white people and less often in other groups) or a high ferritin: without treatment, the extra iron builds up and can damage the liver, heart and pancreas, and NIH notes that treatment includes avoiding iron and vitamin C supplements. Upper limit for adults: 45 mg of elemental iron a day (the elemental iron figure on the label, not the salt weight), because more upsets the stomach and causes constipation; go above it only with blood tests or your clinician's advice (NIH ODS). Iron is deadly to children: keep bottles out of reach. Low iron in men or after menopause needs a search for blood loss. See iron supplements.

Does vitamin D or B12 help tiredness?

Vitamin D: grade C, if your level is low. In 120 otherwise healthy young adults with fatigue and a vitamin D level under 20 µg/L, one 100,000-unit dose by mouth lowered fatigue scores more than placebo at 4 weeks, and 72% against 50% said they felt better (Nowak 2016). That single dose was a trial treatment, not a daily amount. Upper limit for adults: 4,000 IU of vitamin D daily, because too much pushes blood calcium up; anything higher calls for blood tests or a clinician's advice (NIH ODS). See vitamin D supplements.

B12: grade C for no benefit when levels are normal, from one trial. In 95 adults with irritable or inflammatory bowel disease, disabling fatigue and normal B12, B12 tablets at 1,000 mcg daily matched placebo on fatigue over 8 weeks (Scholten 2018); other groups and B12 shots were not tested there. A real deficiency is different: see vitamin B12 for energy.

Thyroid: tiredness with weight gain and feeling cold calls for a TSH test. If you already take thyroid medicine, see supplements and thyroid medicine.

Does a multivitamin give you energy?

B Grade B, small. Pooling 8 placebo-controlled trials in healthy people who took a vitamin and mineral supplement for at least 28 days, fatigue scores fell slightly, as did perceived stress and anxiety; depression did not change (Long 2013). A multivitamin doesn't fix iron deficiency or replace a test. See do you need a multivitamin?

Do rhodiola or ginseng help fatigue?

Rhodiola: grade D. In a systematic review of 11 trials, 3 of 5 found less mental fatigue and 2 of 6 found less physical fatigue, yet each one carried a high or unclear risk of bias; the review called the research contradictory (Ishaque 2012). A later placebo-controlled trial went the other way: in 48 nursing students on shift work, 6 weeks of rhodiola left them more tired than placebo on two fatigue scales, though the authors urge caution in reading the result (Punja 2014). NCCIH says there isn't enough reliable evidence to determine whether rhodiola or its components are useful for any health-related purpose (NCCIH). On our fatigue page, rhodiola's B is for attention, from 3 small trials of one root extract; for tiredness itself, flawed positive trials, a worse-than-placebo result and no pooled analysis leave it at grade D here.

Ginseng: grade C, mixed. A review of 10 studies found modest evidence that Asian or American ginseng eases fatigue in people with chronic illness, with few side effects, and called for better trials (Arring 2018). NCCIH says Asian ginseng might lower blood sugar and may interfere with blood clotting, and that poor sleep is its most common side effect, so check with your pharmacist if you take diabetes medicines or blood thinners. NCCIH also notes it may be unsafe in pregnancy, may worsen autoimmune disease, and has rarely been linked to liver damage (NCCIH). In 364 people with cancer-related fatigue, American ginseng eased fatigue more than placebo at 8 weeks, though not clearly at 4 (Barton 2013); if you're tired during cancer treatment, ask your oncology team before trying it, and see cancer-related fatigue.

Does CoQ10 or anything else help tiredness?

• CoQ10: grade C, small. Pooling 13 trials (1,126 people) in a mix of patient groups and healthy adults, fatigue scores fell modestly against placebo (Tsai 2022). A 2025 review of healthy adults rated the certainty very low to low (Deng 2025). See CoQ10 supplements.
• Beta-glucans: grade B, small. These fibres lowered fatigue scores slightly in healthy adults, pooling 12 trials (Muroya 2025).
• Caffeine wakes you up but doesn't fix the cause, and the FDA lists a fast or pounding heart, high blood pressure, poor sleep, anxiety and jitters among signs of too much. It cites 400 mg a day, about two to three 12-ounce cups of coffee, as an amount not generally linked to negative effects in most adults, and warns that pure or highly concentrated caffeine powders can cause seizures and death (FDA). The 400 mg figure is for adults who aren't pregnant: if you're pregnant, trying to get pregnant or breastfeeding, the FDA suggests asking your health care provider whether to limit caffeine. See caffeine dependence.

Does shilajit give you energy?

D Grade D: one small trial, with a result in a subgroup only, and its contamination risk is real. No placebo-controlled trial has tested shilajit for everyday tiredness; its trials measured muscle strength, hormones and bone. In 63 active young men, 500 mg a day of a shilajit extract for 8 weeks kept more leg strength after a tiring exercise test than placebo, but only in the half with the higher starting strength, and 250 mg did nothing (Keller 2019).

Shilajit is a mineral-rich resin, and a 2024 review counted about 65 metals in it, including lead, arsenic, cadmium and mercury, with some studies above WHO and FDA limits; its authors judged shilajit unsafe to take when its metal content is unknown (Hussain 2024). Thallium, another toxic metal, turned up in raw shilajit and in supplements, sometimes more in the supplements (Kamgar 2025). A pregnant woman taking it for 6 months developed high blood pressure and low potassium (Stavropoulos 2018).

Is adrenal fatigue real?

No: it isn't a recognised medical diagnosis, but the tiredness behind the label is real and worth investigating. The Endocrine Society says no scientific proof supports adrenal fatigue as a true condition, no test can detect it, and accepting the label can delay finding the real cause, such as adrenal insufficiency (a genuine hormone shortage), depression or sleep apnoea (Endocrine Society). A systematic review of 58 studies found no evidence that adrenal fatigue exists (Cadegiani 2016).

The pills sold for it carry their own risk. All 12 "adrenal support" supplements bought in one US study contained thyroid hormone (T3), and most contained at least one steroid hormone, including the prescription steroid budesonide in a quarter of them (Akturk 2018). The Endocrine Society warns that adrenal hormone supplements you don't need can make your own adrenal glands stop working, that they can stay "asleep" for months after you stop, and that this can lead to a life-threatening adrenal crisis.

What about chronic fatigue syndrome?

ME/CFS (myalgic encephalomyelitis, or chronic fatigue syndrome) is a long-term illness in which effort makes symptoms worse. NICE tells clinicians not to offer any medicine or supplement as a treatment that ends it, and to explain that there isn't enough evidence for routine vitamins or minerals to manage symptoms; it flags vitamin D deficiency risk in people who are housebound (NICE NG206). A 2025 review of 14 supplement studies (809 people) found some signals, for example for CoQ10 with NADH and for L-carnitine combinations, but a high risk of bias throughout (Dorczok 2025). See the ME/CFS evidence page.

What we'd skip

• "Adrenal support" and glandular products: hidden thyroid and steroid hormones (Akturk 2018).
• High-dose B12 tablets when your level is normal: no benefit over placebo in one trial of people with bowel disease (Scholten 2018).
• Iron without a test: the trials that found less tiredness enrolled only people with low iron stores (Houston 2018), and extra iron harms people with iron overload.
• Untested shilajit resin: metal contamination (Hussain 2024).
• Pure caffeine powders: the FDA warns they can cause seizures and death (FDA).

Safety and interactions

• Diabetes medicines: ginseng might lower blood sugar, which could add to insulin and other glucose-lowering medicines and cause a low (NCCIH).
• Blood thinners: ginseng may interfere with blood clotting, and CoQ10 can change how warfarin works (see our CoQ10 guide and supplements and blood thinners).
• Rhodiola: NCCIH calls it possibly safe for up to 12 weeks, lists dizziness, headache, poor sleep and dry mouth as side effects, and notes reported interactions with losartan, a blood pressure medicine (NCCIH).
• Iron blocks absorption of thyroid medicine and some antibiotics; space them as their labels say.
• Stimulant stacks: many "energy" blends combine caffeine with guarana or other caffeine sources, so the total can creep past what you meant to take. Check your stack.
• Pregnancy and breastfeeding: tiredness is common, and iron needs change; ask your midwife or obstetric team before any supplement, and avoid shilajit and ginseng.
• Children and teens: tiredness needs their doctor, not an energy product; the FDA notes that medical experts advise against energy drinks for children and teens (FDA).

When to see a doctor

• Go now for chest pain, fainting, severe breathlessness, black or bloody stools, or vomiting blood.
• Book soon for tiredness with weight loss you can't explain, night sweats or fever, breathlessness on mild effort, heavy periods or other bleeding, a lump, or new snoring with daytime sleepiness. Low iron in men or after menopause, or blood in your stools, needs a doctor to look for bleeding in the gut, including bowel cancer (iron supplements).
• Low mood that lasts more than two weeks, or losing interest in things you enjoy, is worth raising; depression is one of the most common causes of tiredness. Thoughts of suicide need help today: in the US, call or text 988; elsewhere, call your emergency number.
• Tiredness lasting more than a few weeks with no clear reason deserves a check-up and the simple blood tests above.

Don't stop or change a prescribed medicine on your own; ask the prescriber or pharmacist whether it could be making you tired.

FAQ

What is the best supplement for energy and fatigue? There isn't one for everyone. Iron helps when your iron stores are low (grade B), and vitamin D helped young adults whose levels were low (grade C). Without a shortage, the best-studied options give small or mixed effects, so test first.

Does B12 give you energy if your levels are normal? Probably not. In 95 adults with bowel disease, fatigue and normal B12, B12 tablets did no better than placebo over 8 weeks.

Is adrenal fatigue real? No. The Endocrine Society says no scientific proof supports it as a true condition, and "adrenal support" supplements tested in the US contained hidden thyroid and steroid hormones.

Does shilajit give you energy? It hasn't been tested against placebo for everyday tiredness (grade D). In one small trial of young men it kept more strength after hard exercise in a subgroup only, and reviews warn about toxic metals in shilajit.

Can tiredness be a sign of something serious? Usually it isn't: sleep problems, depression and stress are the common causes. See a doctor promptly if it comes with weight loss, breathlessness, bleeding, night sweats or low mood.

Related pages

• Fatigue: supplements studied, with grades
• Our fatigue protocol
• Chronic fatigue syndrome protocol
• Depression: the evidence
• Insomnia: the evidence
• Supplements for memory and brain fog
• Supplements for perimenopause
• How we grade evidence

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